Flexible 3D MoS₂–TiO₂ nanorod arrays heterojunction structures for high visible light photocatalysis

Visible light photocatalysis is of great importance in waste water photodegradation and photoelectrochemical clean energy generation. The preparation of visible light photocatalysts with high photocatalytic activity, stability, and recyclability is desirable and challenging. In this paper, we design flexible three-dimensional (3D) MoS₂–TiO₂ nanorod arrays (NRAs) heterojunction structures. Specifically, the peony-shape MoS₂ nanosheets (NS) were loaded on 3D rutile TiO₂ NRAs supported by flexible conductive carbon cloth (CC) substrate by ALD technique and two-step hydrothermal process. The visible light photocatalytic activity of as-prepared flexible 3D MoS₂–TiO₂ NRAs heterojunction structures is about 40 times higher than that of pure rutile TiO₂ NRAs. More importantly, after 7 times cycling tests, the prepared photocatalytic system still holds 98.634 ± 0.936% photodegradation efficiency. The addition of coarse surface MoS₂ NS not only broadens the light adsorption edge to the visible light range but also provides plentiful active reaction sites. The type-II heterojunction formed at the interface between contacted MoS₂ and TiO₂ efficiently prolongs the lifetime of photogenerated electron–hole pairs, inhibiting the recombination of photo-induced carrier. The 3D structures reduce the surface light reflection loss, improving the light utilization efficiency. Moreover, the binder-free combination between photocatalyst and substrate enables fast electron immigration path, promoting carrier separation efficiency. Currently prepared flexible 3D MoS₂–TiO₂ NRAs are capable of an outstanding candidate for large-scale practical visible light or solar light photocatalytic applications.